Read Sharp VC-MH722HM (serv.man9) Service Manual online
38
VC-M522HM
VC-MH722HM
VC-MH732HM
VC-MH722HM
VC-MH732HM
Is the cassette housing distorted?
Fix or replace the cassette housing.
NO
YES
YES
YES
YES
NO
YES
NO
NO
YES
NO
YES
FLOW CHART NO.8 CASSETTE CONTROL TROUBLESHOOTING(1)
A cassette tape is not take in.
NO
NO
Check start sensor cover.
Check line between start sensor and
pin(79) of IC701
Check line between pin(93) of IC701
and pin(11) of IC702.
Is the supply voltage of 12V fed to
pin(13) of IC702?
Check M 12V lines.
Check IC702.
Check line between IC702 and
loading motor.
Replace loading motor.
Is the specified voltage applied at the
loading motor terminal when the
cassette tape is inserted?
Does pin(12) of IC702 change to
about 10V when the cassette tape in
inserted?
Does pin(11) of IC702 go to a "H"
level when the cassette tape is
inserted?
Does pin(79) of IC701 change from
"H" to "L" level when the cassette
tape is inserted?
Does the start sensor cover go to
open when the cassette tape is
inserted?
FLOW CHART NO.6 TIMER TROUBLESHOOTING (2)
Check that the JOG SW has been
securely fitted to the AJ connector.
Securely fit.
Is there a short in the scan outs or
key inputs?
Check if JOG SW harness connect to
the AJ connector on main PWB.
Check that the JOG SW operate normally.
Are the above-shown pulses input
into the pins(54) and (55) of IC701?
Check the signal line from the AJ
connector in the main PWB to the
pins(54) and (55) of IC701.
Replace IC701.
YES
YES
NO
NO
NO
YES
Key-in input is not received
<For jog shuttle mode
.>
Does the key switch make good
contact, when the cassette tape is
inserted?
Check switch contact.
Is there the function control voltage
inputted at the pins(87) and (88) of
IC701, when the keys are activated?
Replace IC701.
Check peripheral circuit of pins(87) and
(88) of IC701, and the function keys.
YES
NO
NO
YES
Key-in input is not received
<Except for jog shuttle mode
.>
SWITCH
FUNCTION
SWITCH
FUNCTION
Ref No.
Ref No.
KEY
OFF
KEY
OFF
5.0V
P801
CASSETTE
4.375V
SW893
TIMER/GAMMA
3.75V
SW885
ST
OP
SW894
S.PICTURE
3.125V
PLA
Y
P802
TEST
2.5V
SW884
P
AUSE/STILL
SW807
MENU
1.875V
SW883
REC
SW881
CH(+)
1.25V
SW810
SET
SW892
EJECT
0.625V
SW882
CH(-)
SW891
ST
ANDBY
0V
KEY
-1(Pin87 of IC701) KEY
-2(Pin88 of IC701)
TERMINAL
VOL
T
AGE
FLOW CHART NO.7 INFRARED R/C TROUBLESHOOTING
No operation is possible from the infrared remote control.
Dose the infrared remote control
function?
Replace infrared remote control as
required.
Is the supply voltage of 5V fed to
C891 of (+) side?
Check AT 5V and GND lines.
Is "L" pulse sent out from pin(1) of
the receiver when the infrared remote
control is activated?
Replace receiver.
Check between at pin(1) of receiver
and all the way up thru to pin(5) of
IC701.
Replace IC701.
YES
NO
YES
NO
NO
NO
YES
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